Unit 2 Case study: The Cellular Level of Organization “Joseph’s story” Question B: Assuming Joseph’s heart has stopped, what cellular processes and membrane functions are going to be affected by the loss of oxygen, blood glucose, and waste removal? As the blood slows and the flow of oxygen and glucose slows, each cells continues to work rapidly burning up its ATP supply. Carbon dioxide builds in the cells and the pH balance begins to drop. Eventually the cells begin to die and the Active transport pumps shut down the plasma membranes of Joseph’s heart. The cells become leaky; sodium slowly began to leak into the cells, and potassium leaked out. Question C: Which intracellular organelles have membranes as part of their structure? How would the breakdown of the membranes of these structures affect the function of Joseph’s heart cells? All intracellular organelles have membranes as a part of their structure. The breakdown of the membranes of these structures affect the function of the heart because the special calcium ATPase’s had stopped moving calcium from the cytosol into the endoplasmic reticulum of his cardiac muscle cells. As the intracellular calcium levels rose, they caused proteases to spill into the interior of the cell, attacking the cytoskeleton. Lysosomal enzymes normally bound safely inside vesicles begin to digest the plasma membranes of the organelles. Question D: Two important pieces of information—the instructions Joseph’s body needs to repair itself and his predisposition for vascular disease—are both contained within the cell on which structures? His predisposition for vascular disease is held in the Mitochondrial DNA. The information that is needed to repair itself is held in the DNA also but is mainly held in the Messenger RNA, which directs the synthesis of specific proteins that can help repair the body. Question E: Joseph’s heart attack has caused the function of his cells to change. What types of proteins in the cell membrane were involved in the homeostatic imbalances of his heart? Ion channel proteins are embedded in the cell membrane and can affect homeostasis by opening or closing thereby allowing or restricting the natural movement of particles toward their homeostatic concentration gradient. Ion pumps can create imbalances as well by pumping ions against their concentration gradients through active transport. The classic example is the sodium potassium ion pump. The cardiovascular system, in addition to needing to maintain itself within certain levels, plays a role in maintenance of other body systems by transporting hormones and nutrients, taking away waste products, and providing all living body cells with a fresh supply of oxygen and removing carbon dioxide. Homeostasis is disturbed if the cardiovascular or lymphatic systems are not functioning correctly. Our skin, bones, muscles, lungs, digestive tract, and nervous, endocrine, lymphatic, urinary and reproductive systems use the cardiovascular